CALLIPER Russian patent published in 2018 - IPC G01B5/12 G01B3/22 

FIELD: measuring equipment.

SUBSTANCE: invention relates to devices for measuring diameters of holes, preferably of complex, conical, type of barrels of barrels of small arms. Gutter includes hollow body 1 with end face 2, three radial openings 3 located at equal distance from abutment end 2 in plane, perpendicular to axis of rotation of body, and with radial hole 4, whose axis is located in a plane perpendicular to axis of rotation of body at distance H in front of plane, in which there are three radial holes, axis of the hole 4 being rotated by angle α° with respect to axis of symmetry, passing through axis of the hollow body and axis of one radial hole 3. Largest angle α° is determined from the dependence α°=(H×360°/t+360°/2n)°, where H is the distance between the planes, in which there are radial holes on the hollow body, t is the step of the pipe cuts, and n is the number of rifling in the pipe. Three measuring supports 7 in the form of a ball are installed in the radial holes 3 of the body 1 without the possibility of falling out. Gage is provided with measuring spacers 12 for measuring cone diameters at different distances from the end of the barrel.

EFFECT: technical result consists in providing objective control of diameters of bullet entrance and cone of chamber preceding it with the presence of cutting surfaces in them.

1 cl, 3 dwg